Toward DSM-IV: a developmental approach to autistic disorder.

As a developmental disorder, autism presents as a combination of unusually delayed maturational stages constrained by neuropathology that also produces many atypical behaviors. This process was labeled atypical ontogeny. To understand the development of autistic symptoms, it is necessary to consider each behavior in the context of what is normal for the child's nonverbal mental age and then the extent to which the behavior is delayed or atypical, given factors such as degree of delay, function, and frequency of expression. Many symptoms of autism are not unique to autism, and many reflect at least in part the underlying degree of mental retardation present in a large proportion of autistic individuals. Given this, it is important to rate autistic symptoms in the context of the child's mental development in areas of intelligence not specifically affected by the autism (i.e., nonverbal intelligence) in order to be sure that the symptom is characteristic of autism and not just reflective of the degree of mental retardation. In order to do this, the clinician must have a good understanding of the normal milestones in development in each of the areas in which autistic children develop symptoms. Developmental examples of both normal and atypical milestones, as well as a reliable indicator of nonverbal level of development, would help a user of the DSM-IV criteria for autistic disorder make more accurate decisions in reaching a diagnosis. The DSM-III-R criteria for autistic disorder have many other problems, such as lack of certain kinds of reliability and validity, poor specificity, and redundancy. Discussion of these problems is beyond the scope of this article but is presented elsewhere. What have been presented here are recommendations for revising DSM-III-R diagnostic criteria for autistic disorder insofar as there are implications for putting developmental psychopathology into a developmental context.